March 1 or Feb. 29, your choice, marked the first day of what is known as meteorological spring. This is the period when weather begins to transform from a relatively settled and cool pattern, and warm air then replaces any threat of snow. However, these warm fronts are often interrupted by a period of showers and then a strong cold front that brings devastation to the heartland.
That's exactly what happened this past week. March got off to a nasty start, with the second day of the month tabulating some 100 tornadoes from Indiana all the way to Lee County, Va. The cause? A very strong cold front that overtook the nation, providing bouts of extremely powerful thunderstorms and torrential rainfall.
For all you non-weather nerds, allow me to explain the concept of a cold front in meteorology. According to the National Oceanic and Atmospheric Administration (NOAA), cold fronts occur when cold air overtakes warm air aloft. We should remember from science classes that cold air is denser than warm air, so the cold air penetrates the warm air mass. The outcome of this relationship between the cold and warm air is concentrated storms. Instability in the upper atmosphere causes an often quick onset of clouds and precipitation.
Compare it to a summer thunderstorm. You can be outside at 1 p.m. and the skies are all blue. By 2:30 p.m., things begin to cloud up. At 2:45 p.m., tree limbs start to sway and large raindrops hit your roof. And then the flood gates open.
Many times, after the front passes, there is no precipitation on its back end. Not to mention, even the clouds are absent from behind the storms. You can sometimes tell a cold front is approaching you by the way the wind is blowing. An approaching front has a warm, southern wind. Once the front passes through, the winds shift from the north and become cooler.
Many times, just by looking at local weather radar, available online via your local news or at weather.gov, the thick lines of clouds represent the front. The thicker the clouds are, the more precipitation you should expect from the front.
This time of the year is particularly dangerous since many cold fronts during the winter months often pass by without anybody even noticing. They lack adequate moisture and cause little problems. However, when cold fronts and their accompanied cold air actually have something a bit warmer to work with, things start to heat up (only not literally).
But the severe threat these storms hold is very literal. To understand the trend of deadly storms better, we have to rely on history. In an article from CBS affiliate WBZ-TV in Boston, Mass., the 2011 weekend of April 17-19 spurred some 200 tornadoes from the middle of the country to the shores of Virginia. More than three dozen people died in a weekend that saw some of the most devastation in Virginia's history.
The reason that last year and this year have been so active is thanks to a very sharp contrast of air. The combination of cold air to the north mixing with above average temperatures in the south is turning out to be a fistfight over which air mass can call the territorial in tornado alley and abroad home. Because of humid, moist air in the Gulf of Mexico pushing into the country's midsection, it is no wonder that the cold air from Canada is mixing to make the perfect recipe for a busy March for emergency personnel.
On Friday, more than a dozen sates reported tornadoes, many of them centered along Kentucky's northern border with Illinois, Indiana and Ohio. Southern Georgia was also affected, as was Eastern Tennessee. As of now, more than 40 people are reported dead in the latest series of wild weather to take place in 2012.
Nevertheless, on Sunday, the nation quieted down with only a handful of weather warnings — for snow — to report. Some of that snow was able to make it to the Farmville area and points to the east.
Weather is definitely a strange phenomenon. And due to changes in weather patterns, each season brings a very new perspective on what can and what will happen. This is just the start of the tornado season. I just hope that we won't have to deal with another March 2 for a long time.
